Crushed Limestone as Foundation/ Base

[HR2503]

Hello!
I have a situation where I need to design the base of a couple of containers placed on the ground. The client wants the containers to be placed over a crushed limestone base. The soil is weak having an SBC of 2500 psf. I am a little confused on how to arrive at some kind of calculations for the thickness of the crushed limestone base.

Any guidance or a spec would be much appreciated.

Best Regards,
HR

 

[GeorgeTheCivilEngineer]

Simply put, thickness required for the load to spread out sufficiently to be below 2500psi. Plus safety factors etc.

Usually a 2 to 1 spread for load through stone.(Two units down, one across).

 

[HR2503]

@GeorgeTheCivilEngineer
Thank you for your response. Unfortunately, I did not understand the "Usually a 2 to spread" part of your comment, could you shed some light on this.

 

[GeorgeTheCivilEngineer]

A load of width 300mm at the surface will spread out through the depth of a layer of stone.

If the stone is 500mm thick this spread is 250mm assuming a 2:1 load dispersal (1:1 would be 500mm). So at the base of the stone layer the load is distributed over a width:

300 + 2 x 500/2 = 800mm

And the pressure reduces accordingly.

I advise looking at geotechnical design guides, for example piling mat design.

This would benefit from a diagram!